miri-script: also overwrite CARGO_BUILD_BUILD_DIR

Author: RalfJung

miri-script/src/util.rs

@@ -62,7 +62,10 @@ impl MiriEnv {
         }
 
         // Hard-code the target dir, since we rely on all binaries ending up in the same spot.
-        sh.set_var("CARGO_TARGET_DIR", path!(miri_dir / "target"));
+        // Cargo provides multiple ways to adjust this and we need to overwrite all of them.
+        let target_dir = path!(miri_dir / "target");
+        sh.set_var("CARGO_TARGET_DIR", &target_dir);
+        sh.set_var("CARGO_BUILD_BUILD_DIR", &target_dir);
 
         // We configure dev builds to not be unusably slow.
         let devel_opt_level =

test-cargo-miri/run-test.py

@@ -183,20 +183,18 @@ def test_cargo_miri_test():
         cargo_miri("test") + ["--target-dir=custom-test"],
         default_ref, "test.empty.ref",
     )
-    del os.environ["CARGO_TARGET_DIR"] # this overrides `build.target-dir` passed by `--config`, so unset it
-    test("`cargo miri test` (config-cli)",
-        cargo_miri("test") + ["--config=build.target-dir=\"config-cli\""],
-        default_ref, "test.empty.ref",
-    )
     if ARGS.multi_target:
-        test_cargo_miri_multi_target()
-
-
-def test_cargo_miri_multi_target():
-    test("`cargo miri test` (multiple targets)",
+        test("`cargo miri test` (multiple targets)",
         cargo_miri("test", targets = ["aarch64-unknown-linux-gnu", "s390x-unknown-linux-gnu"]),
         "test.multiple_targets.stdout.ref", "test.empty.ref",
     )
+    # This must be the last test since we are chaning `os.environ`.
+    del os.environ["CARGO_TARGET_DIR"] # this overrides `build.target-dir` passed by `--config`, so unset it
+    del os.environ["CARGO_BUILD_BUILD_DIR"]
+    test("`cargo miri test` (config-cli)",
+        cargo_miri("test") + ["--config=build.target-dir=\"config-cli\"", "--config=build.build-dir=\"config-cli\""],
+        default_ref, "test.empty.ref",
+    )
 
 args_parser = argparse.ArgumentParser(description='`cargo miri` testing')
 args_parser.add_argument('--target', help='the target to test')